Recently, a treatment of flammable waste such as sludge of industrial waste and a life waste appears to be important social dispute and thus various efficient solutions have been proposed.
Most popular method for treating the flammable waste among them is to minimize a volume of the flammable waste for incinerating or burying it, or throwing out to ocean.
However, the method of burying to the ground, incinerating or throwing out to ocean the flammable waste causes several social problems wherein in a case of a landfill secondary contamination damages caused from leachate and defined area for a landfill causes to limit the method of burying, and further in a case of throwing out to ocean it causes to contaminate the ocean and thus is increasingly prohibited.
Furthermore, in a case of incinerating the flammable waste, contaminated gases containing a plurality of poisonous gases such as dioxin, etc., are emitted directly to atmosphere and thus they cause to deteriorate environment and threaten human health. Additionally, in a case of incinerating the flammable waste combustible, gases are emitted outside, which can be reused as fuel, however, it is impossible to recover and reuse the useful combustible gas through a conventional incinerating method, and thus it wastes natural resource.
In order to solve the above problems various apparatus and methods for incinerating the flammable waste and extracting combustible gases have been developed. However, according the conventional treatment apparatus and method too much time and heat need to remove moisture from the waste and extract combustible gases and thus they cost expensively.
In addition, in taking a consideration of the above matters, other various methods of crushing and compressing the waste have been proposed; however, there are limitations to remove completely air, moisture and gas which are remaining in deep inside the waste and further production of poisonous material during a treatment step is difficult to be avoided and thus a good quality of combustible gases can not be obtained, causing the treatment step not to be practical.
Meanwhile, in order to solve aforementioned problems a waste treatment method using a thermal decomposition has been invented wherein the thermal decomposition refers to a method in which the waste is heated in a state of organic oxygen free or low level of oxygen to produce fuel in a solid, liquid and gaseous state, and in a practical apparatus the waste itself is thermally decomposed without removing air to extract combustible gases. However, according to this thermal decomposition method since the waste is thermally decomposed without removing air, the contaminated gases containing poisonous contaminated material resulted from oxidation and incomplete combustion thereof can be produced.
In order to avoid the above problems Korean Patent registration No. 10-0510818 disclosed a waste treatment method in which thermal decomposition and carbonation procedures were performed in a vacuum state. According to the above disclosure, the waste and the contaminated gas inside a heating furnace were discharged outside by an expansion of over heated water vapor, however, some air was contaminated still and further fuel cost increases due to repeated cooling and reheating.
Furthermore, in order to install components inside the apparatus a worker has to enter directly into the apparatus for his workings such as welding, however, this is only possible in case of installing a big incineration apparatus and impossible in case of installing a middle or small incineration apparatus.
Additionally, according to the aforementioned vacuum method it takes too long time for inside of the furnace to be vacuumed through a cooling thereof, causing a working to be inefficient and further furnace itself is contracted and deformed, causing implementing of the apparatus to be limited.
Meanwhile, a rotary kiln method has been proposed in which a heating furnace is installed laterally in a lengthwise and is rotated through a driving means for the waste to be incinerated by an external heating; however, a problem of poisonous gases emission caused from combustion is not settled since the rotary kiln method is not performed in a vacuum state and further since the driving means has to be prepared separately, causing a configuration and fabrication thereof to be difficult and cost to be expensive. Additionally, since power amount required to rotate a heating furnace having a relative larger capacity is too much and fuel cost necessary for an external heating increase, energy efficiency is low and further recovery of reside waste is difficult, causing an implement thereof to be limited.